Method for preparing walled structures from foamable thermosetting synthetic resinous material

ABSTRACT

Walled structures are prepared of foam-in-place plastic material employing a depositing head having a pair of opposed side forming belts on top of the forming belts which are driven at a predetermined rate. Foamable material is passed to the channel formed by the belts as the depositing or foaming head progresses about the structure.

Unite States atent 91 Smith et al.

METHOD FOR PREPARING WALLED STRUCTURES FROM FOAMABLE THERMOSETTING SYNTHETIC RESINOUS MATERIAL Inventors: Hubert S. Smith, Bay City; Donald R. Wright, Midland, both of Mich.

Assignee: The Dow Chemical Company,

Midland, Mich.

Filed: June 11, 1970 Appl. No.: 45,597

Related US. Application Data Continuation of Ser. No. 785,417, Oct. 7, 1968, abandoned, which is a division of Ser. No. 513,998, Dec. 15, 1965, Pat. No. 3,443,276.

[56] References Cited UNITED STATES PATENTS 3,206,899 9/1965 Wright ..264/ 32 X 3,336,631 8/1967 Smith ..264/47 X 3,336,632 8/1967 Smith ..264/47 X 3,442,992 5/ 1969 Wright ..264/47 X 3,458,609 7/1969 Smith et al. ..264/46 3,383,257 5/1968 James ..264/54 UX 3,154,605 10/1964 Meyer et al. ..264/53 3 172,925 3/1965 Preotle ..264/45 3,443,276 5/1969 Smith et al ..264/47 X Primary ExaminerPhilip E. Anderson Att0rneyGriswold & Burdick ABSTRACT Walled structures are prepared of foam-in-place plastic material employing a depositing head having a pair of opposed side forming belts on top of the forming belts which are driven at a predetermined rate. Foamable material is passed to the channel formed by the belts as the depositing or foaming head progresses about the structure.

10 Claims, 14 Drawing Figures PATliNTLU APR 1 0 375 SHEET 2 [IF 4 INVENTORS. Hub er) 5. 507/ Dona/O R Wkly/77 flLMQQlw PATENTEUAFR 1 01975 SHEET 3 [IF 4 INVENTORS. f/uer/. Sm/ BY Dona/o'R. Wnigh METHOD FOR PREPARING WALLED STRUCTURES FROM FOAMABLE THERMOSETTING SYNTHETIC RESINOUS MATERIAL This application is a continuing application of our co-pending application Ser. No. 785,417, filed Oct. 7, 1968, and now abandoned which is a divisional application of our earlier application Ser. No. 513,998, filed Dec. 15,1965, now U.S. Pat. No. 3,443,276.

This invention relates to the manufacture of walled structures of plastic foam, and more particularly relates to walled structures of plastic foam which are generated incrementally.

U.S. Pat. No. 3,206,899 discloses a method and apparatus for the preparation of walled structures by a process utilizing thermoplastic foam strips which are spirally or helically disposed in a generally continuous manner and adhered to adjacent strips to form a walled structure. Particulate expandable synthetic resinuous thermoplastic materials may also be used to form such structures. The formation of structures from prefoamed components or from particulate expandable plastic materials offers some significant disadvantages. Usually the raw materials from which such structures are prepared must be transported to the building site as foamed elements or as particulate foamable elements which are handled with some difficulty. Further, the particulate foamable particle or elements require a relatively high mold pressure which necessitates rather sturdy molds or forming means. The shipment of plastic foam is relatively expensive because of its low bulk density. The handling of particulate expandable material also offers significant difficulty in transportation to the operating or foam laying head of the apparatus and offers substantial disadvantages because of the heating techniques required to obtain satisfactory expansion and bonding together of the expandable particles to form a unitary body. Foamable or expandable particles or pre-foamed plastic strips have numerous disadvantages when it is desired to incorporate within the wall of the structure various conduits, reinforcements and the like. Expandable particulate particles are not readily formed into intricate shapes. When employing pre-foamed elements, it is costly to use a strip that deviates appreciably from a rectangular cross-section.

It would be particularly advantageous and beneficial if there were available a method which would permit the formation of walled structures from reactive liquid foam producing plastic resin materials. By the term reactive liquid foam producing plastic resin materials" is meant any material which can be handled as a liquid and subsequently cured to form a foam plastic body.

The method of the present invention can be applied to many reactive foam producing materials such as chloromethylated diphenyloxide, epoxy resin compositions, urethane compositions, polyesters, phenol formaldehydes and the like. The different raw materials require different reaction activation techniques. However, the general principle is essentially the same. For example: the chloromethylated diphenyl oxide requires heat activation while the urethanes require intimate mixing of two reactant materials prior to the forming of the polymerized plastic foam.

It is an object of this invention to provide an improved method for the preparation of walled structures from liquid plastic foam producing components.

generation technique having a relatively small diameter.

These benefits and other advantages in accordance with the present invention are achieved in the utilization of an apparatus for the formation of a walled structure by a spiral generating technique which comprises in operative cooperation an operating head support so constructed and arranged so as to position an operating head at a desired location and to successively deposit a synthetic resinuous foam material to form a walled structure, the improvement which comprises an operating head comprising a frame, the frame having a top belt, a first side belt and a second side belt, each of the belts being an endless belt, means to drive the belts at a substantially equal speed, the operating head having a first or front end and a second or rear end, the belts adapted to engage a portion of a foamed structure and propel the operating head in a forward direction, the top belt and first and second side belts defining a channel therebetween, the distance between the side belts being substantially equal to the desired wall thickness of the structure, means to provide a foamable hardenable synthetic resinuous material within the channel formed by the belts.

Also contemplated within the scope of the present invention is a method for the preparation of walled structures from foamed synthetic resinuous material comprising continuously depositing in a generally helical or spiral manner a foamed plastic material, integrally bonding the foamed plastic material to adjacent portions of the foamed plastic material to form a walled structure, the improvement which comprises depositing a foamable hardenable liquid material in a continuous spiral manner, restraining the foamable hardenable material to form a desired configuration and progressively depositing such a material until a desired structure is achieved.

Further features and advantages of the present invention will become more apparent from the following specification taken in connection with the drawing wherein:

FIG. 1 is a schematic illustration of apparatus for practice of the method of the present invention.

FIG. 2 is a side view of one embodiment of a foam depositing and forming head for practice of the method of the present invention;

FIG. 3 is a top view of the apparatus of FIG. 2.

FIG. 4 is a front end view of the apparatus of FIG. 2.

FIG. 5 is a rear end view of the apparatus of FIG. 2.

FIG. 6 is a schematic side view of an alternate embodiment of a material depositing head for practicing the method in accordance with the invention.

FIG. 7 is a top view of the apparatus of FIG. 6.

FIG. 8 is a front view of the apparatus of FIG. 6.

FIG. 9 is a fractional view of the surface of a structure generated employing a material depositing head for practice of the method in accordance with the invention.

FIG. 10 is a sectional view of the wall portion of FIG. 9 taken along the line 10- 10 thereof.

FIG. 11 is a schematic side view of an alternate material depositing head for practice of the method of the present invention.

FIG. 12 depicts a material depositing head for the preparation of hollow walls in accordance with the method of the present invention.

FIG. 13 is a schematic'top view of a material depositing head for practice of the method of the present invention having an articulated body.

FIG. 14 is a schematic representation of a portion of the apparatus of FIG. 13 taken along the line 14-14 of FIG. 13.

In FIG. 1 there is schematically represented a structure being fabricated in accordance with the method of the present invention. An operating head 21 is spirally depositing a synthetic resinous foaming material to form the structure 20. The foam depositing head 21 is moving in the direction indicated by the arrow. A pivot 22 is centrally disposed within the structure 20. The pivot 22 has affixed thereto an arm or boom 23 having a first end 24 pivoted to the pivot 22 in such a manner that the boom 23 may describe a varying solid angle. The arm 23 has a second end 25 which is pivotally affixed to the material depositing head 21. A mobile power and material source 27 is remotely disposed from the structure 20. A plurality of lines 29, 30, 31 and 32 provide communication between the power and material source 27 and the foam depositing head 21. An elevating means 33 adjustably positions the head 21 or eye of the boom 23 in a vertical direction. Alternately, the supply means may be located at any convenient point such as at the pivot 22.

In operation of the apparatus represented in FIG. 1, power and foamable material are supplied from the power and material source 27 through the lines 29, 30, 31 and 32'through rotary joints (not shown) in the pivot 22. The operating head is so constructed and arranged so as to grip the existing portion of the structure 20 and propel itself in the direction indicated by the arrow while simultaneously depositing a quantity of a hardenable foamable material which adheres to the existing structure 20 and increases its height by a predetermined amount generally in the manner of the addition of a foam strip in accordance with U.S. Pat. No. 3,206,899.

In FIGS. 2, 3, 4 and 5 there is schematically depicted a foam depositing head for practice of the method of the present invention generally designated by the reference numeral 35. The foam depositing head 35 comprises in cooperative combination a frame assembly 36, the frame 36 having a first end 37 and a second end 38. The frame assembly 36 defines a first top belt support 40 and a second top belt support 41. The first top belt support 40 has rotatably journaled therein a first top belt drum 43. The second top belt support has rotatably journaled therein a second top belt drum 44. The second top belt support drum 44 has a projecting stub shaft 45. A drive pulley 46 is rigidly affixed to the shaft 45. A top forming belt 47 is supported by the drums 43 and 44. Affixed to the frame 36 is a first side belt assembly 48 and a second side belt assembly 49. The first and second side belt assemblies 48 and 49 are substantially identical and are mirror images of each other. The first side belt assembly 48 affixed to the frame 36 comprises a first roll or drum 50, a second belt roll 51 and a third or rear side belt roll 52. The roll 50 is rotatably affixed to the frame 36 by means of a shaft 54 passing through a suitable bearing, not shown. A dancer roll 53 is disposed generally adjacent the first roll 50. A bearing arm 56 is disposed generally remote from the frame and between the remote terminal portions of the rolls 50 and 51 and is rotatably affixed to the roll 50 by means of the bearing 58 and to the roll 51 by means of the bearing 59. A second bearing arm 60 is disposed generally between the rolls 50 and 51 and is secured to the roll 50 by the bearing 61 and to the roll 51 by the bearing 62. The bearing arms 56 and 60 have disposed thereon a dancer roll support assembly 64 affixed to the arm 60 and a support assembly 65 affixed to the arm 56, respectively. The assemblies 64 and 65 outwardly tension the dancer roll by means of the compression spring 67. A linkage arm having a first end bearing 71 in engagement with the roll 52 and a second end bearing 72 in engagement with the roll 50 in combination with a linkage arm 74 having an end bearing 75 in engagement with the roll 52 and a second end 76 in engagement with the roll 50 serve to space the rolls 50 and 52 and maintain them in generally parallel relationship to each other, whereas the arms 56 and 60 maintain the rolls 51 and 50 in spaced parallel arrangement. A drive pulley 78 is rigidly affixed to the roll 52. A drive pulley 79 is rigidly affixed to the shaft 54 of the roll 50. The pulleys 79 and 78 are connected by a drive belt which causes the rolls 50 and 52 to rotate at identical speeds. A first side belt 82 is in operative engagement with the drums 50, 51, 52 and 53. A similar side belt designated by the suffix a is disposed on the second side belt assembly. A plurality of belt heaters 84, 85, 86 and 87 are in operative engagement with the surface of the side belt 82 adjacent the central portion of the frame 36. The belts 82, 82a and 47 define a centrally disposed channel 90. A belt drive mechanism 98 is supported by the frame 36. The belt drive mechanism 98 comprises a motor 99, a gear head or transmission 100 having an output shaft 101. Rigidly affixed to the output shaft 101 are first and second drive pulleys 102 and 103. The pulley 102 is in operative engagement with a side belt drive shaft 104 rotatably supported within the frame 36 by means of a side belt drive pulley 105 in operative engagement with the drive pulley 102 by means of a belt 107. A pair of bevel gears 109 and 110 are affixed to the shaft 104. The bevel gears 109 and 110 engage bevel gears 111 and 112 affixed to the rolls 50 and 50a, respectively. A belt 113 transmits motion from the pulley 103 to the pulley 46, causing rotation of the drum or roll 44. The drive means is so constructed and arranged that rotation of the shaft 101 in the direction indicated by the arrow causes motion ,of the various drums and pulleys in the indicated direction;

and when the belts are in engagement with a structure being formed the material depositing head progresses in the indicated direction. The frame 36 supports adjacent its first end 37 a material depositing assembly generally designated by the reference numeral 120.

The assembly 120 comprises a mixer motor 121, a mixing chamber 122 containing an agitator, not shown. A foamable material source generally designated by the reference numeral 123 is in operative communication with the mixer chamber 122. A resin discharge conduit 125 is in operative communication with the mixing chamber 122. The conduit 125 has a discharge end 127 remotely disposed from the chamber 122. The discharge end 127 is directed to discharge material into the channel 90 defined by the belts 86, 86a and 87. The assembly 120 is pivotally secured to the frame 36 by means of the pivot 129. A reciprocating means or oscillating cylinder 131 having a linear actuator 132 is in operative engagement with the mixing chamber 122 and is so constructed and arranged so as to permit oscillation of the assembly 120 about the pivot 129 causing a stream issuing from the discharge end 127 of the conduit 125 to traverse the channel 90.

The operation of the material depositing head is depicted in FIGS. 2, 3, 4 and 5. The head is suspended from a suitable boom or suitable operating mechanism as depicted in FIG. 1 by the pivot point 83. The depositing head 35 is placed in engagement with a suitable starter strip. Power is applied to the motor 99 and foamable material supplied to the lines 123. Power is also applied to the motor 121, causing a mixed foamable material to issue from the discharge end 127 of the conduit 125. The oscillating means 131 causes the discharge from the opening 127 to traverse the channel 90. Beneficially, for cleaning and test purposes, the assembly 120 may be pivoted to remove the conduit 125 entirely from the channel 90, and advantageously, the conduit is positioned within the structure being fabricated in order to avoid con amination of the fabricated portion. Rotation of the shaft 101 through the various belts and pulleys causes the side belts 82 and 82a to engage a starter strip and advance the head 35 at a predetermined rate which is sufficient to permit a curing and hardening of the foamable material within the channel 90. Beneficially, heat is applied to the belt heaters 84, 85, 86 and 87, if required. The side belts 82 and 82a are maintained tight by the outward force supplied by the dancer rolls 53 and 530.

In FIGS. 6, 7 and 8 there is illustrated a schematically cutaway side, top and front end view of an alternate embodiment of the apparatus for practice of the method of the invention generally designated by the reference numeral 150. In the schematic illustration of FIGS. 6, 7 and 8, for the sake of clarity, support frames have been omitted. The material depositing head 150 comprises in operative combination side belts 151 and 1510 supported by side belt support front rolls 153 and 153a and rear side support belts or rolls 154 and 154a, respectively. The side belt 151 is provided with a side belt heater 155 and the side belt 1510 provided with a side belt heater 155a. A pair of side belt support plates 157 and 157a are disposed adjacent the inner surfaces of the belts 151 and 151a, respectively. The belts 151 and 151a are driven in the direction indicated by the arrows by means not shown. Each of the belts 151 and 1510 has a structure gripping surface 160 and 160a, respectively, and a foam forming surface 161 and 161a, respectively. A top belt 163 is disposed generally between and at the upper portion of the belts 151 and 151a. The belts 151, 151a and 163 define a channel 165 therebetween. A reinforcing material supply source or spool 167 is disposed generally adjacent the belt 151 and is adapted to feed a web of a fabric reinforcing material to the belt 151 in such a manner that it follows the foam forming surface into the channel 165. A second reinforcing material supply source 167a is oppositely disposed and associated with the belt 151a and feeds a reinforcing material over the belt 151a into the channel 165. The unwound reinforcing material is designated by the reference numerals 168 and 168a, respectively. A foamable hardenable resin mixing and dispensing means 170 is disposed generally adjacent the pulleys 156 and 156a at the front end of the dispensing head 170. The dispensing head 170 has a resin discharge nozzle 171 directed inwardly to the channel 165. The head 170 is pivotally affixed to the roll 154 at a location 173 and is in operative communication with an oscillating means 175.

The operation of the embodiment of apparatus for practicing the method of the invention set forth in FIGS. 6, 7 and 8 is generally similar to the operation of the embodiment set forth in FIGS. 2, 3 and 4 with the exception that the side belts are so constructed and arranged so as to have foam structure gripping surfaces 160 and 160a remotely disposed from the top belt 163 so that a more positive drive of the dispensing head against the deformed structure is obtained. Means to provide a continuous reinforcing material is provided in the embodiment of FIGS. 6, 7 and 8 wherein a continuous reinforcing material such as the webs 168 and 168a are disposed on the inner surface of the belts 151 and 151a and the foamable hardenable material securely adheres to the reinforcing material and a structure with a surface other than a hardenable foamed plastic material is obtained.

In FIGS. 9 and 10 there is illustrated fractional and sectional views of a wall structure generally designated by the reference numeral 180. FIG. 10 is a sectional view of the wall section taken along the line 10- 10 of FIG. 9. The wall 180 comprises a plurality of foamed layers or turns 181 disposed one on top of each other in the general relationship as depicted in FIG. 1. A plurality of skin or surface strips 182 are disposed on the surface of the foamed layers 181, each of the strips 182 defines a plurality of openings 183 adjacent one edge thereof; the openings 183 are disposed toward the upper edge of the strip 182. A lower edge 185 of the skin strip overlaps the aperture 183 permitting a foaming material to penetrate or pass through the aperture 183 and contact the inner surface of the lower edge 185, thereby adhering the inner skin strips 182 to each other. Similarly, outer skins 187 are disposed on the opposite sides of the wall and define like apertures 188 adjacent the upper edge thereof.

Employing the embodiment of FIGS. 6, 7 and 8, a wide variety of reinforcing elements or strips may be incorporated into a spirally generated foam structure. The strips or skins may vary from an open mesh screen, as depicted in FIGS. 6 and 8, to a metal skin such as is illustrated in FIGS. 9 and 10. Such skins are readily prepared from fabrics of synthetic filaments, natural fibers, wire, sheet metal, flexible synthetic resinous sheet or strip such as polyethylene, nylon, polypropylene, polyvinylchloride, flexible polyesters, resin-impregnated fabrics, paper and the like. Highly desirable and variable internal and external finishes are readily achieved. If desired, it is not necessary to apply simultaneously an inner and outer skin, but an inner or outer skin is readily prepared by feeding a surface finishing material from an appropriate spool or supply source.

In FIG. 11 there is schematically illustrated a cutaway view of an alternate embodiment for practice of the method of the invention generally designated by the reference numeral 200. The apparatus 200 comprises in cooperative combination a frame or support means, not shown, which supports a foam depositing head 201. The head 201 comprises a mixer section 202 and a foamable material depositing nozzle 203. A head oscillating means 205 is in operative combination with the head 201 adapted to reciprocate the head transversely with respect to the direction of travel of the assembly 200. A first side forming belt assembly 207, a second side forming belt assembly 209 and a top forming belt assembly 211 are disposed and driven in a manner similar to the embodiments of FIGS. 2-8. The top assembly 211 comprises a forming belt 212, a belt support 213, a first drum 214 and a second drum 215 and a forming belt heater 216. A conduit supply means 220 is in operative combination with the foamed depositing assembly 200. The conduit supply means 220 comprises a central support mandrel 221 having a conduit 223 wound thereon. A plurality of guide and straightening rolls 224, 225, 226, 227, 228, 229, 230 and 231 guide'and position the conduit 223 into a channel 235 defined by the side belt assemblies 208, 209 and the top belt assembly 211. The guide rolls 229 and 230, as well as the guide roll 231, serve to position the conduit 223 at a predetermined location within the channel 235. A foam layer 237 is illustrated and deposited by the assembly 200 which is moving in the direction indicated by the arrow. The foam layer 237 contains a portion of the conduit 223. The foam layer 237 is bonded to a previously deposited foam layer 239 which also contains a portion of the conduit 223. Em- I ploying the apparatus of FIG. 1 1, a conduit of a desired shape and size is readily disposed within a foam layer deposited by the foam depositing head and permanently embedded therein. Beneficially, the conduit is preheated (by means not shown) in cases where the foamable material is not sufficiently exothermic. The conduit, beneficially, may serve as reinforcement in a structural sense as well as a conduit for heat exchange fluids, wires and the like.

In- FIG. 12 there is depicted a schematic, fractional cutaway view of an alternate embodiment for practice of the method of the invention designated by the reference numeral 250. The embodiment 250 comprises an upper forming belt assembly 251 which comprises an endless belt 252 supported by a drum 253 and a drum 254. A belt heater 255 is disposed adjacent the belt 252; a belt support plate 256 is disposed within the belt 251 and adjacent the area wherein foamable material is deposited. A first side belt assembly 257 is disposed adjacent the top belt assembly 251 and is generally similar in configuration to the side belt assembly in FIGS. 2-8. A second side belt assembly 258 is oppositely disposed to the side belt assembly 257. The belt assemblies 251, 257 and 258 form a generally rectangular channel 260 and in combination with a previously deposited layer of foam 261 form a closed rectangular space. A foam depositing head 262 is disposed within the-channel 260. The foam depositing head 262 comprises in cooperative combination a housing 263 having a foamable resinuous material supply means, not shown. The housing 263 defines a first foam component passageway 264, a second foam component passageway 265, a mixing chamber 266 and a foam exit port 267. A motor or mixer rotating means 269 is affixed to the housing 263 and is operatively connected to a rotatable shaft 270 passing through the housing 263 and is generally coaxial with the channel 260. A plurality of agitator blades 272 affixed to the shaft 270 are disposed within the mixing chamber 266. The shaft 270 terminates adjacent the outlet 267 in a generally discoidal rotary distributor head or slinger 274. A foamable resinous material 275 is propelled generally radially outwardly from the discharge opening 267 by the head 274. The material 275 is deposited on the surface defining the channel 260 where it foams to form a hollow generally rectangular tube of foamed material 276 which is bonded to an adjacent hollow rectangular tube of foamed material 276a. The embodiment of FIG. 12, operates in a manner generally similar to the embodiment of FIGS. 2-8, with the exception that the rotary distributor head or slinger 274 applies a controlled amount of foamable material to the walls of the channel defined by the belt assembly 251, 257, 258 and the previously deposited material 261 to form a hollow tube wherein each layer or turn of the spiral is a hollow rectangular conduit. Beneficially, the embodiment of FIG. 12 is employed when constructing the enclosures of the maximum size wherein it is desirable to obtain as thick a wall aspossible and yet utilize a minimum amount of material compatible with good engineering practice.

FIG. 13 illustrates an alternate embodiment for practicing the method of the invention, generally designated by the reference numeral 280. The embodiment 280 is schematically illustrated. Much of the necessary support members and drive means and foam depositing heads have been omitted for the sake of clarity. The embodiment 280 comprises an articulated frame 281. The articulated frame 281 comprises a first segment 282, a second segment 283, a third segment 284, a fourth segment 285, a fifth segment 286, a sixth segment 287, a seventh segment 289, an eighth segment 290 and a ninth segment 291. Each segment is connected to an adjacent segment by means of the connecting links 292, 293, 294, 295, 296, 297, 298, 299 and 300, respectively. Each of the links 292-300 is pivotally attached to the adjacent segments and adapted to pivot in a plane containing the visible surface of the segments. A top forming belt assembly 302 is disposed in such a manner that a portion of a top belt 303 passes within the segments and the links lie between the upper and lower surfaces of the top belt. A first side belt assembly 304 is disposed generally adjacent one edge of the top belt assembly 302. A second side belt assembly 306 is oppositely disposed to the first side belt assembly 304. The side belt assemblies 304 and 306 in combination with the top belt assembly 302 define a channel 307. A first reinforcing strip spool 309 is disposed generally adjacent the side belt 304 and delivers reinforcing strip 310 to the outer surface of the side belt assembly 304. A second reinforcing strip supply means 313 is disposed generally adjacent the side belt assembly 306 and delivers a strip of reinforced material 314 to the side belt assembly 306. A foam depositing head is incorporated in the apparatus at a location generally adjacent the left hand portion of the Figure and is adapted to deposit foam in the channel 307 generally in the manner illustrated in the previous embodiments. The forming apparatus 280 is adapted to travel in the direction indicated by the arrow.

In FIG. 14 there is illustrated a schematic sectional representation of the apparatus 280 taken on a line 1414 of FIG. 13. FIG. 14 depicts one of the segments 286, the location of the top belt 303 passing through a slot 308 defined within the segment 286. Connecting links 296 and 295 are shown pivotally attached to the segment 286. The segment 286 has pivotally supported therein a first side roller 311 and a second side roller 312. The side rollers 311 and 312 engage the first side belt 304 and the second side belt 306, respectively, and maintain it in a position to provide a rectangular crosssection of the channel 307. The rollers 311 and 312 are pivotally supported on shafts 315 and 316, respectively.

In operation of the embodiment as depicted in FIGS. 13 and 14, foamed material is provided to the channel 307 generally in accordance with the manner employed in the previously described embodiment. The side of the top belts are driven in the appropriate direction to cause the foam depositing apparatus 280 to progress at a suitable rate along a previously prepared base material of the desired curvature. Because of the articulated construction, each of the segments 282, 233, 284, 285, 286, 287, 288, 289, 290 and 291 are free to pivot in a plane generally parallel to a panel containing a surface of the upper belt assembly. The side belts conform to a relatively small or varying radius of curvature and deposit foamable hardenable material in a channel with a generally curved configuration and a rectangular curved cross-section. The side rollers such as the rollers 311 and 312 are present in each of the segments and cause the side belts to conform to the desired configuration.

Beneficially, the embodiment illustrated in FIGS. 13 and 14 is particularly adaptable for the rapid construction of spiral generated structures in that a depositing head of relatively greater length can be employed and for a given foamable, hardenable composition. The rate of deposition is proportional to the length of the curing zone which, in essence, is about the length of the channel defined by the forming belts in which the foamable, hardenable material is deposited.

By way of further illustration, employing a foam depositing head generally in accordance with FIGS. 2-5 wherein the channel defined by the forming belts is 2 feet in length and 2 inches in width and about 3 inches in depth, a -40 foot diameter (ground level dimension) dome is constructed utilizing a spiral generation technique employing a foamable self-extinguishing polyurethane composition which comprises a first component (a) which is a mixture of lsocyanate Component Material Parts by Weight Polymethylene polyphenyl isocyanate 146.4 Tris-B'chloroethyl phosphate 32.6

Silicone glycol copolymer 2.2

The second component (b) comprises a mixture of an amine polyglycol which is the condensation product of 1 ml. ethylene diamine, 1 ml. ethylene peroxide and 3 ml. propylene oxide, 7l parts by weight; trichlorofluoromethane, 47.8 parts by weight; nitromethane, 2.2 parts by weight and N,N-dimethyl ethanol amine, 1.3 parts by weight.

Components (a) and (b) are fed to the foam depositing head in a ratio of 1.5 parts of(a) to 1 part of(b) at a rate of about 0.63 pound per minute to deposit a strip of foam having a density of about 2 pounds per cubic foot and at a rate of about 0.3 cubic foot per minute. The foam depositing nozzle is a portion of a inch pipe (nominal size). The components (a) and (b) are mixed at a temperature of about C. and cured to a tack-free condition in from 15 to 20 seconds. The belts defining the channel are coated with polytetrafluoroethylene and heated to a temperature of 140F. The linear speed of deposition is about 6 feet per minute. The resultant foamed polyurethane dome shows a good bonding between adjacent turns of the deposited foam and a smooth upper surface.

Sampling of the dome walls indicates that each turn of the foam strip is a generally rectangular section wherein the density of the foam increases sharply toward the outer surfaces, thereby providing an element having a high modulus and excellent strength per unit weight of material deposited. In all cases, low pressure (less than 10 pounds per square inch) is exerted on the belts.

In a manner similar to the foregoing illustration and employing an apparatus substantially as illustrated in FIGS. 68, a 30 foot dome is prepared employing the foamable components of the previOus illustration and applying as reinforcing webs glass fiber woven cloth having a thickness of about 10 mils and mesh openings of approximately 1/ 10 inch square. The webs are about 3% inches in width and each web overlaps the adjacent web. Excellent bonding of the glass fiber cloth to the foam is observed. Similar beneficial results are achieved when strips of paper, cotton fabric, aluminum sheet, copper sheet, steel sheet, copper fabric, steel fabric, aluminum fabric, polystyrene sheet, polyvinylchloride sheet, polyester fabric, glass reinforced sheet are adhered to the surface of a spirally generated structure to provide reinforcement and surface decoration.

Utilizing an apparatus generally as depicted in FIG. 11, inch (nominal) copper tubing is disposed within a polyurethane strip having a generally square crosssectional configuration and measuring about 2.75 inches per side. The tubing is warmed to a temperature of about F. prior to introduction into the channel defined by the forming belts. The thermal conductivity of the copper tubing is sufficient that warming is required in order to obtain adequate curing and foaming of the resinous material adjacent the tube.

In a generally similar manner, A inch (nominal) thin wall aluminum electrical conduit is disposed within a foam structure. Utilizing an apparatus generally in accordance with FIG. 12, spirally generated foam structures are prepared utilizing the foamable composition previously set forth to provide a hollow deposited strip of generally square cross-section and measuring about 4% inches per side. By varying the feed rate of the polyurethane composition wall thickness is readily varied to provide a solid foam strip having a thickness as low as one-fourth inch.

Similar beneficial results are achieved when the following foamable, hardenable compositions are employed.

Composition A A mixture of 44.5 parts by weight phenol, 55.5 parts of an aqueous formaldehyde solution of 37 weight percent concentration and 1.5 parts sodium hydroxide is reacted at 60C. for 6 hours. At this stage of the reaction, the liquid condensation product is water soluble. The mixture is then acidified by addition of 33 cc. of aqueous sulphuric acid of 30 percent concentration per pound of the mixture to which the acid is added. The acidified mixture is agitated, while warmed to about 40C. for from 2 to 3 hours. The aqueous and organic layers of the mixture are separated and the organic layer washed thoroughly with water. The water-insoluble liquid phenolformaldehyde product thus obtained retains from to 35 percent of water dissolved therein.

The resultant resin is subjected to vacuum at a temperature of about 28C. until about 13 percent by weight of the total mixture has been removed. The weight loss is water. Twenty parts of the resin are admixed with 1.8 parts trichlorotrifluorocthane (Freon 113) and heated to 45C. Concentrated aqueous hydrochloric acid is continuously admixed with the resin-trichlorotrifluoroethane mixture and a tack-free expanded phenolic foam is obtained 15 seconds after mixing.

Composition B Twenty parts by weight of the phenolformaldehyde resin of Composition A is admixed with 1 part by weight phenol, l .8 parts by weight trichlorotrifluoroethane. On admixture of 22.8 parts of the resin-phenolhalogenated ethane mixture with 2.5 parts of concentrated hydrochloric acid, a tack-free foam is obtained 12 seconds after mixing.

Composition C Component (1) is a liquid epoxy resin of the epichlorohydrin-bisphenol type prepared by the reaction of excess epichlorohydrin with Bisphenol A in the presence of sodium hydroxide to provide a prepolymer having an average epoxide equivalent weight of about 240, and subsequently removing the excess epichlorohydrin. The resultant prepolymer is a viscous liquid. Eighty parts by weight of the viscous liquid are admixed with 19.5 parts by weight of trichloromonofluoromethane and 0.5 part by weight of a silicone glycol copolymer sold under the description of DC-l l3 and utilized to control the cell size of the resultant foam. Component 2 comprises 72 parts by weight of tris-2,3-dibromopropylphosphate, 25.3 parts by weight of triethylene glycol and 2.7 parts by weight of boron trifluoride. One hundred parts of Component I l are admixed with 7.1 parts of Component 2 and a rigid plastic foam which is tack-free is obtained 15 seconds after mixing.

Other foamable, hardenable compositions well known to those skilled in the art are useful in preparing structures in accordance method of the present invention.

As is apparent from the foregoing specification, the

present invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set forth and defined in the hereto appended claims.

What is claimed is:

1. In a method for the preparation of walled structures from foamable thermosetting synthetic resinous material, the method comprising continuously depositing in a generally helical or spiral manner a foamable hardenable thermosetting synthetic resinous liquid material which cures to form a foamed plastic body, the liquid material being deposited within a mold configuration peripherally surrounding the deposited material until the material has hardened to form a desired predetermined configuration of hardened foamed resinous material, integrally bonding adjacent portions of the foamed resinous material and progressively depositing such material until a desired structure is achieved, the improvement which comprises distributing the hardenable foamable thermosetting liquid synthetic resinous material peripherally within the mold configuration in the form of a generally rectangular hollow tube and in a quantity sufficient that on foaming the material forms a hollow strip.

2. The method of claim 1 including the step of restraining the thermosetting foamable hardenable material within a heated configuration.

3. The method of claim 1 wherein the thermosetting foamable hardenable material is a polyurethane resin composition.

4. The method of claim 1 wherein the thermosetting foam-able hardenable material is a phenolic resin composition.

5. The method of claim 1 wherein the material is an epoxy resin composition.

6. The method of claim 1 including the step of confining the thermosetting foamable hardenable liquid resin on at least one surface by means of an adherent reinforcing web.

7. The method of claim 6 wherein the rein-forcing web is a perforate web.

8. The method of claim 1 including the step of applying a reinforcing skin to at least one surface of the structure as it is being fabricated and adhering the skin to the structure and to an adjacent skin in overlapping relationship.

9. The method of claim 1 wherein the thermosetting foam-able hardenable material is confined by endless belts forming an enclosed channel in combination with a previously deposited foamed strip.

10. The method of claim 1 wherein the material is selected from the group consisting of foamable epoxy H resin, foamable phenolformaldehyde resin and foamable urethane resin, foamable polyesters and foamable chloromethylated diphenyloxide compositions.

t t s a 

2. The method of claim 1 including the step of restraining the thermosetting foamable hardenable material within a heated configuration.
 3. The method of claim 1 wherein the thermosetting foamable hardenable material is a polyurethane resin composition.
 4. The method of claim 1 wherein the thermosetting foam-able hardenable material is a phenolic resin composition.
 5. The method of claim 1 wherein the material is an epoxy resin composition.
 6. The method of claim 1 including the step of confining the thermosetting foamable hardenable liquid resin on at least one surface by means of an adherent reinforcing web.
 7. The method of claim 6 wherein the rein-forcing web is a perforate web.
 8. The method of claim 1 including the step of applying a reinforcing skin to at least one surface of the structure as it is being fabricated and adhering the skin to the structure and to an adjacent skin in overlapping relationship.
 9. The method of claim 1 wherein the thermosetting foam-able hardenable material is confined by endless belts forming an enclosed channel in combination with a previously deposited foamed strip.
 10. The method of claim 1 wherein the material is selected from the group consisting of foamable epoxy resin, foamable phenolformaldehyde resin and foamable urethane resin, foamable polyesters and foamable chloromethylated diphenyloxide compositions. 